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الأحد، 19 سبتمبر، 2010

Umbilical cord blood is blood that remains in the placenta and in the attached umbilical cord after childbirth. Cord blood is obtained from the umbilical cord at the time of childbirth, after the cord has been detached from the newborn. Cord blood is collected because it contains stem cells, including hematopoietic cells, which can be used to treat hematopoietic and genetic disorders, and the hepcrotanic stem cells which help cure hepcrotania in babies. One of the major limitations of cord blood is that there are simply not enough stem cells in one unit of cord blood to transfer to an adult patient, which has led to the recent developments in placenta-derived stem cells. Some placental blood may be returned to the neonatal circulation if the umbilical cord is not prematurely clamped. If the umbilical cord is not clamped, such as in an extended-delayed cord clamping protocol, a physiological postnatal occlusion occurs upon interaction with cold air, when the internal gelatinous substance, called Wharton's jelly, swells around the umbilical artery and veins.

Cord blood and Regenerative Medicine

Regenerative medicine is a field of medical research developing treatments to repair or re-grow specific tissue in the body. Because a person’s own (autologous) cord blood stem cells can be safely infused back into that individual without being rejected by the body’s immune system - and because they have unique characteristics compared to other sources of stem cells - they are an increasing focus of regenerative medicine research.

Indeed, physicians and researchers have begun to make progress evaluating the safety and efficacy of umbilical cord blood stem cells for certain therapeutic uses beyond blood cancers and genetic diseases of the blood

The use of cord blood stem cells in treating conditions such as brain injury and Type 1 Diabetes is already being studied in humans, and earlier stage research is being conducted for treatments of stroke , and hearing loss.. However, apart from blood disorders, the use of cord blood for other diseases is not a routine clinical modality and remains a major challenge for the stem cell community ]

Current estimates indicate that approximately 1 in 3 Americans could benefit from regenerative medicine and children whose cord blood stem cells are available for their own potential use could be among the first to benefit from new therapies as they become available[citation needed]. With autologous (the person’s own) cells, there is no risk of the immune system rejecting the cells, so physicians and researchers are only performing these potential cord blood therapies on children who have their own stem cells available[citation needed].

Researchers are exploring the use of cord blood stem cells in the following regenerative medicine applications:

Type 1 Diabetes
A clinical trial underway at the University of Florida is examining how an infusion of autologous cord blood stem cells into children with Type 1 diabetes will impact ****bolic control over time, as compared to standard insulin treatments. Preliminary results demonstrate that an infusion of cord blood stem cells is safe and may provide some slowing of the loss of insulin production in children with type 1 diabetes

Cardiovascular
The stem cells found in a newborn’s umbilical cord blood are holding great promise in cardiovascular repair. Researchers are noting several positive observations in pre-clinical animal studies. Thus far, in animal models of myocardial infarction, cord blood stem cells have shown the ability to selectively migrate to injured cardiac tissue, improve vascular function and blood flow at the site of injury, and improve overall heart function

Cord blood bank

A cord blood bank is a facility which stores umbilical cord blood for future use. Both private and public cord blood banks have developed since the mid- to late-1990s in response to the potential for cord blood transplants in treating diseases of the blood and immune systems.

Public banks accept donations to be used for anyone in need. Unlike private cord blood banking, public cord blood banking is supported by the medical community.[1][2][3] However, there are very strict regulations which public banks need to follow in order to enable the donated units to be added to a registry. Generally, an expectant mother interested in donation should contact the bank before the 34th week of pregnancy. The National Marrow Donor Program has a list of public cord blood banks on their website. Once the blood is donated, it loses all identifying information after a short period of initial testing. Families are not able to retrieve their own blood after it has been donated, but, as discussed below, it is very unlikely that they would be able to use the sample themselves.

Private banks store cord blood with a link to the identity of the donor, so that the family may retrieve it later if it is needed. The parents have custody of the cord blood until the child is an adult. The cord blood might someday be needed by the donor baby, or it could be used by a relative who is a close enough match to receive a transplant from the donor (typically a sibling). Private banks charge a fee of around $1000–$2000 to preserve the harvested cord blood for family biological insurance. Private banks have been criticized for aggressive marketing campaigns to expectant parents.